Process of making alkyl-barbituric acids.



UNITED STATES PATENT oTTTon.

ALFRED EINHORN, OF MUNICH, GERMANY, ASSIGNOR TO FARBWERKE VORM. MEISTER, LUOIUS & BRUNING, OF HOOHST-ON-THE-MAIN, GER- MANY, A CORPORATION OF GERMANY.

PROCESS OF MAKING ALKYL-BARBITURIC ACIDS.

Specification of Letters Patent.

Patented July 25, 1905.

Application filed November 28, 1904. Serial No" 234,516.

To all whom it nuty concern.-

Be it known that I, ALFRED EINHORN, Dr. Rer. Nat, professor of chemistry,-a citizen of the Empire of Germany, residing at Munich, Germany, have invented certain new and useful Improvements in the Manufacture of Alkyl-Barbituric Acids, of which the following is a specification.

I have found that carbonates of phenols when heated with alkyl-malonamids may .be transformed into derivatives of barbituric acid, the reaction corresponding to the following equation:

CONH2 Alphyl o The reaction is analogous to that observed by Oazeneuve on heating oxalamid with phenylcarbonate, (Comptes 'rendus, 129, 834;) but while Oazeneuve obtained only a yield of five per cent. of parabanic acid that of alkyl-barbituric acids is up to fifty per cent. and more of the theoretical yield if in the process the temperature at which the reaction takes place be kept for a considerable time.

The process may be carried out, for instance, as follows:

Example 1: Five grams diethyl-malonamid are heated with twenty grams of phenyl carbonate to 200 to 220 centigrade. The phenol formed may be distilled off together With the OO+2Alphyl OH excess ofphenyl carbonate. After heating for eighteen hours the residue is treated With dilute caustic-soda lye, the undissolved phenyl carbonate is filtered off, and from the solution the diethyl-barbituric acid may be separated in the known manner. 3. 5 grams of diethyl-barbituric acid are obtained.

Example 11: One gram of diethyl-malonamid is heated with three grams of phenylethyl carbonate from 210 to 220 centigrade for fifteen hours, and from the residue the diethyl-barbituric acid is obtained in the quantity of 0.2 gram.

Having now described my invention, what I claim is 1. The process herein described for the manufacture of alkyl-barbituric acids, which consists in heating carbonates of phenols With alkyl-malonarnids.

2. The process herein described for the manufacture of diethyl-barbituric acid, Which consists in heating diphenyl carbonate With diethyl-malonamid.

3. The process herein described for the manufacture of diethyl-barbituric acid, which consists in heating diphenyl carbonate with diet-hyl-malonamid for a considerable time to a temperature of from 190 to 250 centigrade.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

ALFRED EINHORN.

WVitnesses:

ULYSSES J. BYWATER, ABRAHAM SCI'ILESINGER, 

